// Include Jomsocial core
$jspath = JPATH_ROOT.DS.'components'.DS.'com_community';
include_once($jspath.DS.'libraries'.DS.'core.php');
// Return current user
$user =& CFactory::getUser();
// Return user with given id
$user =& CFactory::getUser($userId);

Using Jomsocial functions in outside of Jomsocial

joomla

PHP